A widely-used circuit module includes a circuit substrate on which at least one mount component is mounted and a peripheral of the mount component is sealed by a sealing body made of a synthetic resin etc. In such a circuit module, a surface of the sealing body is coated with a conductive material to be used as a shield against interruption induced by electromagnetic waves (hereinafter referred to as electromagnetic interruption). The electromagnetic interruption is interference, unnecessary radiation or the like, for example. By providing the shield, the electromagnetic interruption caused by the electromagnetic waves emitted from the mount component in the shield against electronic devices etc. outside of the shield is prevented (emission is improved), or the electromagnetic interruption caused by the electromagnetic waves emitted outside from the shield against the mount component in the shield is prevented (immunity is improved).
For example, Japanese Patent Application Laid-open No. 2006-286915 discloses a circuit module where electronic components mounted on a circuit substrate are sealed by an insulating resin layer, and a surface of the insulating resin layer is covered by a conductive resin layer. The conductive resin layer offers a noise shielding effectiveness.